How tight should the cylinder be on a 625 JM 45ACP?

I can move mine enough, even so small but it makes an audible metal sound? Should it move at all or be very tight? I can move it side to side and front to back to make the sound.

Thanks....

Afternoon Shoote;

A little cyl rotational play at lock up is perfectly normal on the S&W. That allows cyl hole to line up with forcing cone as bullet passes between them.


To measure cyl end shake:

Use feeler gauges to measure with--

Gently push the cylinder forward (& hold there) then measure the cyl to barrel-extension gap.
Then gently push (& hold) the cylinder to the rear and measure cyl to barrel-extension gap again.
Subtract the held-forward from the held-rearward , and that is the amount of end shake in the cylinder.

Do this for 5 or 6 different cylinder clocking's (you might find a bit of variance)

The often used (not sure its official though) spec for S&W is a Minimum of .002" with a Maximum of .006".

Personally I think .006" is W-A-Y too much end shake. I try to set my personal guns to about .001" -.0015" at the tightest place in the cylinder clocking.

Added: if you are planning on shooting very fast with quick reloads & no downtime between re-loads you might want to set a bit looser so the cyl doesn't bind as it gets hot & stretches out.

Setting to the tight side keeps the cylinder from pounding on the recoil shield with heavy magnum loads.

Woverine

Will check per your suggestions. Thanks for the well -written info.